The research is directed toward the isolation, purification and characterization of the cytochrome P-450 form(s) responsible for the 20-monooxygenation of Alpha-ecdysone in mitochondria and microsomes of a representative insect species. The hydroxylating system will be reconstituted in vitro and the properties of the hemoprotein(s) will be analyzed in terms of amino acid composition, immunochemical reactions and peptide mapping. It is hoped that the work will provide a better understanding of the role, of the 20-monooxygenase reaction in insect post-embryonic and adult development and may result in the formulation of rational control strategies for insects of medical and economic interest.